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1.  Analysis of nevirapine (NVP) resistance in HIV-infected infants who received extended NVP or NVP/zidovudine prophylaxis 
AIDS (London, England)  2011;25(7):911-917.
BACKGROUND
In the PEPI-Malawi trial, infants received up to 14 weeks of extended nevirapine (NVP) or extended NVP plus zidovudine (NVP+ZDV) to prevent postnatal HIV transmission. We examined emergence and persistence of NVP resistance in HIV-infected infants who received these regimens prior to HIV diagnosis.
METHODS
Infant plasma samples collected at 14 weeks of age were tested using the ViroSeq HIV Genotyping System and a sensitive point-mutation assay, LigAmp (for K103N and Y181C). Samples collected at 6 and 12 months of age were analyzed using LigAmp.
RESULTS
At 14 weeks of age, NVP resistance was detected in samples from 82 (75.9%) of 108 HIV-infected infants. While the frequency of NVP resistance detected by ViroSeq was lower in the extended NVP+ZDV arm than in the extended NVP arm, the difference was not statistically significant (38/55=69.1% vs. 44/53=83.0%, P=0.12). Similar results were obtained using LigAmp. Using LigAmp, the proportion of infants who still had detectable NVP resistance at 6 and 12 months was similar among infants in the two study arms (at 6 months: 17/20=85.0% for extended NVP vs. 21/26=80.8% for extended NVP+ZDV, P=1.00; at 12 months: 9/16=56.3% for extended NVP vs.10/13=76.9% for extended NVP+ZDV, P=0.43).
CONCLUSIONS
Infants exposed to extended NVP or extended NVP+ZDV had high rates of NVP resistance at 14 weeks of age, and resistant variants frequently persisted for 6–12 months. Frequency and persistence of NVP resistance did not differ significantly among infants who received extended NVP only vs. extended NVP+ZDV prophylaxis.
doi:10.1097/QAD.0b013e328344fedc
PMCID: PMC3261770  PMID: 21487249
HIV; nevirapine; resistance; infants; Malawi
2.  Efficacy of Short-Course AZT Plus 3TC to Reduce Nevirapine Resistance in the Prevention of Mother-to-Child HIV Transmission: A Randomized Clinical Trial 
PLoS Medicine  2009;6(10):e1000172.
Neil Martinson and colleagues report a randomized trial of adding short-course zidovudine+lamivudine to reduce drug resistance from single-dose nevirapine used to prevent mother-to-child transmission of HIV.
Background
Single-dose nevirapine (sdNVP)—which prevents mother-to-child transmission of HIV—selects non-nucleoside reverse-transcriptase inhibitor (NNRTI) resistance mutations in the majority of women and HIV-infected infants receiving it. This open-label, randomised trial examined the efficacy of short-course zidovudine (AZT) and lamivudine (3TC) with sdNVP in reducing NNRTI resistance in mothers, and as a secondary objective, in infants, in a setting where sdNVP was standard-of-care.
Methods and Findings
sdNVP alone, administered at the onset of labour and to the infant, was compared to sdNVP with AZT plus 3TC, given as combivir (CBV) for 4 (NVP/CBV4) or 7 (NVP/CBV7) days, initiated simultaneously with sdNVP in labour; their newborns received the same regimens. Women were randomised 1∶1∶1. HIV-1 resistance was assessed by population sequencing at: baseline, 2, and 6 wk after birth. An unplanned interim analysis resulted in early stopping of the sdNVP arm. 406 pregnant women were randomised and took study medication (sdNVP 74, NVP/CBV4 164, and NVP/CBV7 168). HIV-1 resistance mutations emerged in 59.2%, 11.7%, and 7.3% of women in the sdNVP, NVP/CBV4, and NVP/CBV7 arms by 6 wk postpartum; differences between NVP-only and both NVP/CBV arms were significant (p<0.0001), but the difference between NVP/CBV4 and NVP/CBV7 was not (p = 0.27). Estimated efficacy comparing combined CBV arms with sdNVP was 85.6%. Similar resistance reductions were seen in infants who were HIV-infected by their 6-wk visit.
Conclusions
A short course of AZT plus 3TC, supplementing maternal and infant sdNVP, reduces emergent NNRTI resistance mutations in both mothers and their infants. However, this trial was not powered to detect small differences between the CBV arms.
Trial registration
www.ClinicalTrials.gov NCT 00144183
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Currently, about 33 million people are infected with the human immunodeficiency virus (HIV), which causes AIDS. HIV can be treated with combination antiretroviral therapy (ART), commonly three individual antiretroviral drugs that together efficiently suppress the replication of the virus. HIV infection of a child by an HIV-positive mother during pregnancy, labor, delivery, or breastfeeding is called mother-to-child transmission (MTCT). In 2007, an estimated 420,000 children were newly infected with HIV, the majority through MTCT. Most of these mothers and children live in sub-Saharan Africa where child and maternal mortality rates are high and mortality in HIV-infected children is extremely high. MTCT is preventable and there is a global commitment, agreed at the UN General Assembly Session on HIV/AIDS in 2001, to reduce the proportion of infants infected with HIV by 50% by 2010.
Why Was This Study Done?
In many resource-limited settings, MTCT is prevented by giving a single dose of nevirapine (an antiretroviral drug which has a long duration in the body and protects the fetus during labor and delivery only) to HIV-infected women in labor and also to a baby within 72 hours of birth. However, nevirapine, a non-nucleoside reverse-transcriptase inhibitor (NNRTI), which suppresses the replication of the virus, is associated with increased resistance of HIV, in mother and child, to NNRTI. This resistance reduces the effectiveness of future treatments of both mother and child with combination ART that includes an NNRTI; such regimens are the mainstay for long-term treatment of HIV in developing countries. The researchers investigated whether giving other antiretroviral drugs with nevirapine, during labor and delivery, to both mother and her newborn reduced the chances of them developing resistance to NNRTIs.
What Did the Researchers Do and Find?
The researchers selected 406 HIV-positive pregnant women for study across five sites in South Africa between February 2003 and May 2007. The women and their newborn babies were randomly assigned to receive, either (i) a single dose of nevirapine, (ii) a single dose of nevirapine plus combivir (zidovudine combined with lamivudine) for four days, or (iii) a single dose of nevirapine plus combivir for seven days. At two days, two weeks, and six weeks after delivery blood was collected from mothers and babies. HIV virus from blood samples was analyzed for resistance mutations, and mothers and children with resistance mutations were monitored for a further 96 weeks until no resistance was detected or combination ART (also called “HAART”) was started. Enrollment into the single-dose nevirapine arm was stopped early because a very high rate of NNRTI resistance mutations was found and other investigators reported long-term bad consequences of NNRTI-resistance on subsequent ART. The two nevirapine plus combivir arms were continued. The researchers found that selection of resistance mutations by single-dose nevirapine was reduced in mother and child by the addition of zidovudine and lamivudine for a short period; resistance mutations were found in 59.2% of women who got nevirapine only but only 11.7%, and 7.3% of women treated nevirapine plus four days combivir, and nevirapine plus seven days combivir respectively. A reduction was also seen in new NNRTI resistant mutations in the HIV-infected infants that received combivir. The study did not have enough women to show that there was a real difference between the resistance in the four-day and seven-day combivir regimens.
What Do These Findings Mean?
These findings show that a short-course treatment of zidovudine and lamivudine in addition to a single dose of nevirapine during labor and birth reduces the selection of NNRTI resistance mutations in both mother and child. The drug regimens appeared safe, and easy to provide and adhere to. Preliminary results from this study contributed to a change in clinical practice for the care of pregnant women with HIV; in 2004 the World Health Organisation guidelines introduced a short course of combivir with nevirapine for the management of pregnant HIV-infected women. However, the study had some limitations. It used HIV-positive women who were mainly infected with a subtype of HIV called HIV-1 clade C and who had a lot of virus in their blood. NNRTI resistance after treatment with nevirapine is more common in clade C than in others and this study does not address the effect of these combinations for preventing NNRTI resistance in other HIV subtypes. Also, World Health Organization, national, and international guidelines recommend combination ART during pregnancy, as it decreases HIV transmission from mother to child in the uterus to <2% in resource-limited settings. Although long-term combination treatment may not be available in all locations, this study does not tell us how the short-term combinations during and after delivery tested would compare to longer-term combinations given to pregnant women in reducing both HIV transmission and HIV drug resistance.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000172.
This study is further discussed in a PLoS Medicine Perspective by Lehman et al.
The US Centers for Disease Control and Prevention provide information for HIV treatment and prevention
MedlinePlus provides extensive information on symptoms and treatment for HIV/AIDS as well as access to related clinical trials and medical literature
aidsmap, a nonprofit, nongovernmental organization provides information on HIV and supporting those living with HIV
The World Health Organization gives information on the prevention of mother-to-child transmission of HIV
doi:10.1371/journal.pmed.1000172
PMCID: PMC2760761  PMID: 19859531
3.  Impact of Maternal and Infant Antiretroviral Drug Regimens on Drug Resistance in HIV-Infected Breastfeeding Infants 
The Pediatric infectious disease journal  2013;32(4):10.1097/INF.0b013e31827f44ee.
BACKGROUND
The HPTN 046 trial evaluated the efficacy of extended infant nevirapine (NVP) administration for prevention of HIV transmission through breastfeeding. Infants received daily NVP to 6 weeks of age. HIV-uninfected infants (the intent-to-treat group) received daily NVP or placebo up to 6 months of age. We analyzed emergence of NVP resistance in infants who acquired HIV-infection despite prophylaxis.
METHODS
HIV genotyping was performed using the ViroSeq HIV Genotyping System. Medians and proportions were used to summarize data. Two-sided Fisher’s exact tests were used to evaluate associations between categorical variables.
RESULTS
NVP resistance was detected in 12 (92.3%) of 13 infants who were HIV-infected by 6 weeks and in seven (28%) of 25 infants who were HIV-uninfected at 6 weeks and HIV-infected at 6 months of age (6/8=75% in the NVP arm, 1/17=5.9% in the placebo arm, P=0.001). Among those 25 infants, 4 had mothers who initiated an antiretroviral (ARV) treatment regimen by 6 months postpartum. In all 4 cases, the treatment regimen included a non-nucleoside reverse transcriptase inhibitor (NVP or efavirenz). NVP resistance was detected in all four of those infants by 6 months of age (4/4=100%). In contrast, only three (14.2%) of the remaining 21 HIV-infected infants whose mothers did not initiate ARV treatment developed NVP resistance (P=0.003).
CONCLUSIONS
Extended NVP prophylaxis significantly increased the risk of NVP resistance in infants who acquired HIV infection after 6 weeks of age. Treatment of maternal HIV infection was also associated with emergence of NVP resistance in HIV-infected, breastfed infants.
doi:10.1097/INF.0b013e31827f44ee
PMCID: PMC3826537  PMID: 23249916
Nevirapine resistance; prevention of mother-to-child transmission; extended nevirapine; HIV
4.  Analysis of nevirapine (NVP) resistance in Ugandan infants who were HIV-infected despite receiving single dose (SD) nevirapine (NVP) vs. SD NVP plus daily NVP up to 6-weeks of age to prevent HIV vertical transmission 
The Journal of infectious diseases  2008;198(7):1075-1082.
Background
Single dose (SD) nevirapine (NVP) at birth plus NVP to the infant up to 6 weeks of age is superior to SD NVP alone for prevention of HIV vertical transmission through breastfeeding. We analyzed NVP resistance in HIV-infected Ugandan infants who received either SD NVP or extended NVP prophylaxis.
Methods
We tested plasma HIV using a genotyping assay (ViroSeq), a phenotypic resistance assay (PhenoSense), and sensitive point mutation assay (LigAmp, for K103N, Y181C, G190A).
Results
At 6 weeks, NVP resistance was detected by ViroSeq in a higher proportion of infants in the extended NVP arm than in the SD NVP arm (21/25=84% vs. 12/24=50%, p=0.01). Similar results were obtained with LigAmp and PhenoSense. Infants who were HIV-infected at birth had high rates of resistance in both study arms. In contrast, infants who were HIV-infected after birth were more likely to have resistance detected at 6 weeks in the extended NVP arm. Use of extended NVP prophylaxis was also associated with detection of NVP resistance by ViroSeq at 6 months (7/7=100% extended NVP arm vs. 1/6=16.7% SD NVP arm, p=0.005).
Conclusions
Use of extended NVP prophylaxis was associated with increased selection and persistence of NVP resistance in HIV-infected Ugandan infants.
doi:10.1086/591503
PMCID: PMC2587235  PMID: 18684096
HIV-1; infant; mother-to-child transmission; nevirapine; resistance
5.  18-Month Effectiveness of Short-Course Antiretroviral Regimens Combined with Alternatives to Breastfeeding to Prevent HIV Mother-to-Child Transmission 
PLoS ONE  2008;3(2):e1645.
Objective
We assessed the 18-month effectiveness of short-course (sc) antiretroviral peripartum regimens combined with alternatives to prolonged breastfeeding to prevent mother-to-child transmission (MTCT) of HIV-1 in Abidjan, Côte d'Ivoire.
Methodology
HIV-1 infected pregnant women received from ≥32–36 weeks of gestation scZidovudine (ZDV)+/−Lamivudine (3TC)+single-dose Nevirapine (sdNVP) at delivery within the ANRS 1201/1202 DITRAME-Plus cohort (2001–2003). Neonates received a sdNVP+7-day ZDV prophylaxis. Two infant-feeding interventions were systematically offered free of charge: formula-feeding or exclusive shortened breastfeeding with early cessation from four months. The reference group was the ANRS 049a DITRAME cohort (1994–2000) exposed to scZDV from 36 weeks, then to prolonged breastfeeding. Pediatric HIV infection was defined by a positive plasma HIV-1 RNA at any age, or if aged ≥18 months, a positive HIV-1 serology. Turnbull estimates of cumulative transmission risks (CTR) and effectiveness (HIV-free survival) were compared by exposure group using a Cox model.
Findings
Among 926 live-born children enrolled, 107 (11.6%) were HIV-infected at 18 months. CTRs were 22.3% (95% confidence interval[CI]:16–30%) in the 238 ZDV long-term breastfed reference group, 15.9% (CI:10–27%) in the 169 ZDV+sdNVP shortened breastfed group; 9.4% (CI:6–14%) in the 195 ZDV+sdNVP formula-fed group; 6.8% (CI:4–11%) in the 198 ZDV+3TC+sdNVP shortened breastfed group, and 5.6% (CI:2–10%) in the 126 ZDV+3TC+sdNVP formula-fed group. Each combination had a significantly higher effectiveness than the ZDV long-term breastfed group except for ZDV+sdNVP shortened breastfed children, ranging from 51% (CI:20–70%) for ZDV+sdNVP formula fed children to 63% (CI:40–80%) for ZDV+3TC+NVPsd shortened breastfed children, after adjustment for maternal eligibility for antiretroviral therapy (ART), home delivery and low birth-weight. Substantial MTCT risk reductions are reachable in Africa, even in short-term breastfed children. The two sc antiretroviral combinations associated to any of the two infant feeding interventions, formula-feeding and shortened breastfeeding, reduce significantly MTCT with long-term benefit until age 18 months and without increasing mortality.
doi:10.1371/journal.pone.0001645
PMCID: PMC2237904  PMID: 18286200
6.  Nevirapine Resistance and Breast-Milk HIV Transmission: Effects of Single and Extended-Dose Nevirapine Prophylaxis in Subtype C HIV-Infected Infants 
PLoS ONE  2009;4(1):e4096.
Background
Daily nevirapine (NVP) prophylaxis to HIV-exposed infants significantly reduces breast-milk HIV transmission. We assessed NVP-resistance in Indian infants enrolled in the “six-week extended-dose nevirapine” (SWEN) trial who received single-dose NVP (SD-NVP) or SWEN for prevention of breast-milk HIV transmission but who also acquired subtype C HIV infection during the first year of life.
Methods/Findings
Standard population sequencing and cloning for viral subpopulations present at ≥5% frequency were used to determine HIV genotypes from 94% of the 79 infected Indian infants studied. Timing of infection was defined based on when an infant's blood sample first tested positive for HIV DNA. SWEN-exposed infants diagnosed with HIV by six weeks of age had a significantly higher prevalence of NVP-resistance than those who received SD-NVP, by both standard population sequencing (92% of 12 vs. 38% of 29; p = 0.002) and low frequency clonal analysis (92% of 12 vs. 59% of 29; p = 0.06). Likelihood of infection with NVP-resistant HIV through breast-milk among infants infected after age six weeks was substantial, but prevalence of NVP-resistance did not differ among SWEN or SD-NVP exposed infants by standard population sequencing (15% of 13 vs. 15% of 20; p = 1.00) and clonal analysis (31% of 13 vs. 40% of 20; p = 0.72). Types of NVP-resistance mutations and patterns of persistence at one year of age were similar between the two groups. NVP-resistance mutations did differ by timing of HIV infection; the Y181C variant was predominant among infants diagnosed in the first six weeks of life, compared to Y188C/H during late breast-milk transmission.
Conclusions/Significance
Use of SWEN to prevent breast-milk HIV transmission carries a high likelihood of resistance if infection occurs in the first six weeks of life. Moreover, there was a continued risk of transmission of NVP-resistant HIV through breastfeeding during the first year of life, but did not differ between SD-NVP and SWEN groups. As with SD-NVP, the value of preventing HIV infection in a large number of infants should be considered alongside the high risk of resistance associated with extended NVP prophylaxis.
Trial Registration
ClinicalTrials.gov NCT00061321
doi:10.1371/journal.pone.0004096
PMCID: PMC2606064  PMID: 19119321
7.  Short Communication: In Utero HIV Infection Is Associated with an Increased Risk of Nevirapine Resistance in Ugandan Infants Who Were Exposed to Perinatal Single Dose Nevirapine 
Use of single dose nevirapine (sdNVP) to prevent HIV mother-to-child transmission is associated with the emergence of NVP resistance in many infants who are HIV infected despite prophylaxis. We combined results from four clinical trials to analyze predictors of NVP resistance in sdNVP-exposed Ugandan infants. Samples were tested with the ViroSeq HIV Genotyping System and a sensitive point mutation assay (LigAmp, for detection of K103N, Y181C, and G190A). NVP resistance was detected at 6–8 weeks in 36 (45.0%) of 80 infants using ViroSeq and 33 (45.8%) of 72 infants using LigAmp. NVP resistance was more frequent among infants who were infected in utero than among infants who were diagnosed with HIV infection after birth by 6–8 weeks of age. Detection of NVP resistance at 6–8 weeks was not associated with HIV subtype (A vs. D), pre-NVP maternal viral load or CD4 cell count, infant viral load at 6–8 weeks, or infant sex. NVP resistance was still detected in some infants 6–12 months after sdNVP exposure. In this study, in utero HIV infection was the only factor associated with detection of NVP resistance in infants 6–8 weeks after sdNVP exposure.
doi:10.1089/aid.2009.0003
PMCID: PMC2752753  PMID: 19552593
8.  Short Communication: In Utero HIV Infection Is Associated with an Increased Risk of Nevirapine Resistance in Ugandan Infants Who Were Exposed to Perinatal Single Dose Nevirapine 
Abstract
Use of single dose nevirapine (sdNVP) to prevent HIV mother-to-child transmission is associated with the emergence of NVP resistance in many infants who are HIV infected despite prophylaxis. We combined results from four clinical trials to analyze predictors of NVP resistance in sdNVP-exposed Ugandan infants. Samples were tested with the ViroSeq HIV Genotyping System and a sensitive point mutation assay (LigAmp, for detection of K103N, Y181C, and G190A). NVP resistance was detected at 6–8 weeks in 36 (45.0%) of 80 infants using ViroSeq and 33 (45.8%) of 72 infants using LigAmp. NVP resistance was more frequent among infants who were infected in utero than among infants who were diagnosed with HIV infection after birth by 6–8 weeks of age. Detection of NVP resistance at 6–8 weeks was not associated with HIV subtype (A vs. D), pre-NVP maternal viral load or CD4 cell count, infant viral load at 6–8 weeks, or infant sex. NVP resistance was still detected in some infants 6–12 months after sdNVP exposure. In this study, in utero HIV infection was the only factor associated with detection of NVP resistance in infants 6–8 weeks after sdNVP exposure.
doi:10.1089/aid.2009.0003
PMCID: PMC2752753  PMID: 19552593
9.  Quantifying the Impact of Nevirapine-Based Prophylaxis Strategies To Prevent Mother-to-Child Transmission of HIV-1: a Combined Pharmacokinetic, Pharmacodynamic, and Viral Dynamic Analysis To Predict Clinical Outcomes▿† 
Antimicrobial Agents and Chemotherapy  2011;55(12):5529-5540.
Single-dose nevirapine (sd-NVP) and extended NVP prophylaxis are widely used in resource-constrained settings to prevent vertical HIV-1 transmission. We assessed the pharmacokinetics of sd-NVP in 62 HIV-1-positive pregnant Ugandan woman and their newborns who were receiving sd-NVP prophylaxis to prevent mother-to-child HIV-1 transmission. Based on these data, we developed a mathematical model system to quantify the impact of different sd-NVP regimens at delivery and of extended infant NVP prophylaxis (6, 14, 21, 26, 52, 78, and 102 weeks) on the 2-year risk of HIV-1 transmission and development of drug resistance in mothers and their breast-fed infants. Pharmacokinetic parameter estimates and model-predicted HIV-1 transmission rates were very consistent with other studies. Predicted 2-year HIV-1 transmission risks were 35.8% without prophylaxis, 31.6% for newborn sd-NVP, 19.1% for maternal sd-NVP, and 19.7% for maternal/newborn sd-NVP. Maternal sd-NVP reduced newborn infection predominately by transplacental exchange, providing protective NVP concentrations to the newborn at delivery, rather than by maternal viral load reduction. Drug resistance was frequently selected in HIV-1-positive mothers after maternal sd-NVP. Extended newborn NVP prophylaxis further decreased HIV-1 transmission risks, but an overall decline in cost-effectiveness for increasing durations of newborn prophylaxis was indicated. The total number of infections with resistant virus in newborns was not increased by extended newborn NVP prophylaxis. The developed mathematical modeling framework successfully predicted the risk of HIV-1 transmission and resistance development and can be adapted to other drugs/drug combinations to a priori assess their potential in reducing vertical HIV-1 transmission and resistance spread.
doi:10.1128/AAC.00741-11
PMCID: PMC3232796  PMID: 21947390
10.  What Will It Take to Eliminate Pediatric HIV? Reaching WHO Target Rates of Mother-to-Child HIV Transmission in Zimbabwe: A Model-Based Analysis 
PLoS Medicine  2012;9(1):e1001156.
Using a simulation model, Andrea Ciaranello and colleagues find that the latest WHO PMTCT (prevention of mother to child transmission of HIV) guidelines plus better access to PMTCT programs, better retention of women in care, and better adherence to drugs are needed to eliminate pediatric HIV in Zimbabwe.
Background
The World Health Organization (WHO) has called for the “virtual elimination” of pediatric HIV: a mother-to-child HIV transmission (MTCT) risk of less than 5%. We investigated uptake of prevention of MTCT (PMTCT) services, infant feeding recommendations, and specific drug regimens necessary to achieve this goal in Zimbabwe.
Methods and Findings
We used a computer model to simulate a cohort of HIV-infected, pregnant/breastfeeding women (mean age, 24 y; mean CD4, 451/µl; breastfeeding duration, 12 mo). Three PMTCT regimens were evaluated: (1) single-dose nevirapine (sdNVP), (2) WHO 2010 guidelines' “Option A” (zidovudine in pregnancy, infant nevirapine throughout breastfeeding for women without advanced disease, lifelong combination antiretroviral therapy for women with advanced disease), and (3) WHO “Option B” (pregnancy/breastfeeding-limited combination antiretroviral drug regimens without advanced disease; lifelong antiretroviral therapy with advanced disease). We examined four levels of PMTCT uptake (proportion of pregnant women accessing and adhering to PMTCT services): reported rates in 2008 and 2009 (36% and 56%, respectively) and target goals in 2008 and 2009 (80% and 95%, respectively). The primary model outcome was MTCT risk at weaning.
The 2008 sdNVP-based National PMTCT Program led to a projected 12-mo MTCT risk of 20.3%. Improved uptake in 2009 reduced projected risk to 18.0%. If sdNVP were replaced by more effective regimens, with 2009 (56%) uptake, estimated MTCT risk would be 14.4% (Option A) or 13.4% (Option B). Even with 95% uptake of Option A or B, projected transmission risks (6.1%–7.7%) would exceed the WHO goal of less than 5%. Only if the lowest published transmission risks were used for each drug regimen, or breastfeeding duration were shortened, would MTCT risks at 95% uptake fall below 5%.
Conclusions
Implementation of the WHO PMTCT guidelines must be accompanied by efforts to improve access to PMTCT services, retain women in care, and support medication adherence throughout pregnancy and breastfeeding, to approach the “virtual elimination” of pediatric HIV in Zimbabwe.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
A woman who is infected with HIV can pass the virus to her baby during pregnancy, labor and delivery, or breastfeeding—mother-to-child HIV transmission (MTCT). Without treatment, up to 30% of babies born to HIV-infected women will become infected with HIV during pregnancy or at delivery, and a further 5%–20% will become infected through breastfeeding. In 2009, around 400,000 children under 15 years of age became infected with HIV, mainly through MTCT—90% of these MTCT infections occurred in Africa.
In addition to preventing HIV infection among prospective parents and avoiding unwanted pregnancies among HIV-positive women, effective prevention of MTCT (PMTCT) requires preventing the transmission of HIV from infected mothers to their infants during pregnancy, labor, delivery, and breastfeeding.
In 2010, the World Health Organization (WHO) published new guidelines for PMTCT based on combination antiretroviral therapy for women with advanced HIV disease, and two options for countries to select for women with less advanced disease. Option A includes zidovudine (ZDV) during pregnancy and single-dose nevirapine (sdNVP) at delivery, followed by daily nevirapine syrup for infants throughout the duration of breastfeeding; Option B includes maternal triple-drug ARV regimens throughout pregnancy and breastfeeding. However, WHO estimates that only 53% of pregnant women worldwide received any antiretroviral medicines for PMTCT in 2009.
Why Was This Study Done?
As in many sub-Saharan African countries where prolonged breastfeeding is common, and necessary to improve child health, Zimbabwe is implementing the 2010 WHO guidelines with Option A. However, because of the challenges of enrolling and retaining women in PMTCT programs, the effectiveness of this strategy is unknown. Therefore in this study, the researchers used a model to calculate the level of PMTCT uptake in Zimbabwe, the PMTCT drug regimens, and the duration of breastfeeding that would be necessary to reach the WHO goal of an MTCT risk below 5%.
What Did the Researchers Do and Find?
The researchers used a validated computer simulation model developed for analyzing the cost-effectiveness of preventing AIDS complications to measure risk of infant HIV transmission at the time of weaning, the HIV infection risk at 4–6 weeks of age, infant survival at two years of age, and 2-year HIV-free survival. The researchers used four scenarios of PMTCT uptake and linked the models to two populations of pregnant and breastfeeding women (mean age, 24 years) in Zimbabwe, and then analyzed the combinations of the factors necessary to reach MTCT risks less than 5%.
At baseline, the researchers found that the 2008 National PMTCT Program in Zimbabwe led to a projected 12-month MTCT risk of 20.3%. The projected risk in 2009 was 18.0% because of improved uptake. The estimated MTCT risk with Option A at 56% uptake (2009 levels) was 14.4% and with Option B was 13.4%. However, even with greatly increased uptake, such as 95% levels, the researchers found that projected transmission risks would exceed the WHO goal of less than 5% MTCT, and that the MTCT risk would fall below 5% at the 95% uptake level only if the lowest transmission risks were used for each drug regimen, or if breastfeeding duration were shortened.
What Do These Findings Mean?
These findings show that the planned implementation of the 2010 WHO PMTCT guidelines with Option A in Zimbabwe could substantially reduce infant HIV infection risk compared to the 2009 national program with sdNVP. Furthermore, in order to reach a MTCT risk of less than 5%, a national program based on either Option A or Option B will also need to include strategies to improve access to PMTCT services (to almost 100% uptake), retain women in care, and support medication adherence throughout pregnancy and breastfeeding. These findings from a resource-limited country with high HIV prevalence and prolonged breastfeeding may be useful for other countries in sub-Saharan Africa.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001156.
Avert gives some more information on MTCT and PMTCT.
The United Nations Children's Fund has factsheets on national PMTCT responses in the most affected countries.
WHO's strategic vision for PMTCT for 2010–2015 is also available.
doi:10.1371/journal.pmed.1001156
PMCID: PMC3254654  PMID: 22253579
11.  HIV-1 persists in breast milk cells despite antiretroviral treatment to prevent mother-to-child transmission 
AIDS (London, England)  2008;22(12):1475-1485.
Background
The effects of short-course antiretrovirals given to reduce mother-to-child transmission (MTCT) on temporal patterns of cell-associated HIV-1 RNA and DNA in breast milk are not well defined.
Methods
Women in Kenya received short-course zidovudine (ZDV), single-dose nevirapine (sdNVP), combination ZDV/sdNVP or short-course highly active antiretroviral therapy (HAART). Breast milk samples were collected two to three times weekly for 4–6 weeks. HIV-1 DNA was quantified by real-time PCR. Cell-free and cell-associated RNA levels were quantified by the Gen-Probe HIV-1 viral load assay.
Results
Cell-free HIV-1 RNA levels in breast milk were significantly suppressed by sdNVP, ZDV/sdNVP or HAART therapy compared with ZDV between day 3 and week 4 postpartum (P ≤ 0.03). Breast milk HIV-1 DNA levels (infected cell levels) were not significantly different between treatment arms at any timepoint during the 4–6-week follow-up. At 3 weeks postpartum, when the difference in cell-free RNA levels was the greatest comparing HAART directly with ZDV (P = 0.0001), median log10 HIV-1 DNA copies per 1 × 106 cells were 2.78, 2.54, 2.69, and 2.31 in the ZDV, sdNVP, ZDV/sdNVP and HAART arms, respectively (P = 0.23). Cell-associated HIV-1 RNA levels were modestly suppressed in HAART versus ZDV/sdNVP during week 3 (3.37 versus 4.02, P = 0.04), as well as over time according to a linear mixed-effects model.
Conclusion
Cell-free and, to a lesser extent, cell-associated HIV-1 RNA levels in breast milk were suppressed by antiretroviral regimens used to prevent MTCT. However, even with HAART, there was no significant reduction in the reservoir of infected cells, which could contribute to breast milk HIV-1 transmission.
doi:10.1097/QAD.0b013e328302cc11
PMCID: PMC2765916  PMID: 18614871
antiretrovirals; breast milk; cell associated; HIV; vertical transmission; viral load
12.  Nevirapine- Versus Lopinavir/Ritonavir-Based Initial Therapy for HIV-1 Infection among Women in Africa: A Randomized Trial 
PLoS Medicine  2012;9(6):e1001236.
In a randomized control trial, Shahin Lockman and colleagues compare nevirapine-based therapy with lopinavir/ritonavir-based therapy for HIV-infected women without previous exposure to antiretroviral treatment.
Background
Nevirapine (NVP) is widely used in antiretroviral treatment (ART) of HIV-1 globally. The primary objective of the AA5208/OCTANE trial was to compare the efficacy of NVP-based versus lopinavir/ritonavir (LPV/r)-based initial ART.
Methods and Findings
In seven African countries (Botswana, Kenya, Malawi, South Africa, Uganda, Zambia, and Zimbabwe), 500 antiretroviral-naïve HIV-infected women with CD4<200 cells/mm3 were enrolled into a two-arm randomized trial to initiate open-label ART with tenofovir (TDF)/emtricitabine (FTC) once/day plus either NVP (n = 249) or LPV/r (n = 251) twice/day, and followed for ≥48 weeks. The primary endpoint was time from randomization to death or confirmed virologic failure ([VF]) (plasma HIV RNA<1 log10 below baseline 12 weeks after treatment initiation, or ≥400 copies/ml at or after 24 weeks), with comparison between treatments based on hazard ratios (HRs) in intention-to-treat analysis. Equivalence of randomized treatments was defined as finding the 95% CI for HR for virological failure or death in the range 0.5 to 2.0. Baseline characteristics were (median): age = 34 years, CD4 = 121 cells/mm3, HIV RNA = 5.2 log10copies/ml. Median follow-up = 118 weeks; 29 (6%) women were lost to follow-up. 42 women (37 VFs, five deaths; 17%) in the NVP and 50 (43 VFs, seven deaths; 20%) in the LPV/r arm reached the primary endpoint (HR 0.85, 95% CI 0.56–1.29). During initial assigned treatment, 14% and 16% of women receiving NVP and LPV/r experienced grade 3/4 signs/symptoms and 26% and 22% experienced grade 3/4 laboratory abnormalities. However, 35 (14%) women discontinued NVP because of adverse events, most in the first 8 weeks, versus none for LPV/r (p<0.001). VF, death, or permanent treatment discontinuation occurred in 80 (32%) of NVP and 54 (22%) of LPV/r arms (HR = 1.7, 95% CI 1.2–2.4), with the difference primarily due to more treatment discontinuation in the NVP arm. 13 (45%) of 29 women tested in the NVP versus six (15%) of 40 in the LPV/r arm had any drug resistance mutation at time of VF.
Conclusions
Initial ART with NVP+TDF/FTC demonstrated equivalent virologic efficacy but higher rates of treatment discontinuation and new drug resistance compared with LPV/r+TDF/FTC in antiretroviral-naïve women with CD4<200 cells/mm3.
Trial registration
ClinicalTrials.gov NCT00089505
Please see later in the article for the Editors' Summary
Editors' Summary
Background
About 34 million people (mostly living in low- or middle-income countries) are currently infected with HIV, the virus that causes AIDS. HIV destroys CD4 lymphocytes and other immune cells, leaving infected individuals susceptible to other infections. Early in the AIDS epidemic, most HIV-infected people died within 10 years of infection. Then, in 1996, antiretroviral therapy (ART)—cocktails of drugs that attack different parts of HIV—became available. For people living in affluent countries, HIV/AIDS became a chronic condition. But, because ART was expensive, for people living in developing countries, HIV/AIDS remained a fatal illness. In 2006, the international community set a target of achieving universal access to ART by 2010 and, although this target has not been reached, by the end of 2010, 6.6 million of the estimated 15 million people in need of ART in developing countries were receiving one of the ART regimens recommended by the World Health Organization (WHO) in its 2010 guidelines.
Why Was This Study Done?
A widely used combination for the initial treatment of HIV-infected people (particularly women) in resource-limited settings is tenofovir and emtricitabine (both nucleotide reverse transcriptase inhibitors; reverse transcriptase is essential for HIV replication) and nevirapine (NVP, a non-nucleoside reverse transcriptase inhibitor). However, little is known about the efficacy of this NVP-based ART combination. Moreover, its efficacy and toxicity has not been compared with regimens containing lopinavir/ritonavir (LPV/r). LPV/r, which inhibits the viral protease that is essential for HIV replication, is available in resource-limited settings but is usually reserved for second-line treatment. LPV/r-based ART is more expensive than NVP-based ART but if it were more effective or better tolerated than NVP-based ART, then first-line treatment with LPV/r-based ART might be cost-effective in resource-limited settings. Conversely, evidence of the clinical equivalence of NVP-based and LPV/r-based ART would provide support for NVP-based ART as an initial therapy. In this randomized equivalence trial, the researchers compare the efficacy and toxicity of NVP-based and LVP/r-based initial therapy for HIV infection among antiretroviral-naïve African women. In a randomized trial, patients are assigned different treatments by the play of chance and followed to compare the effects of these treatments; an equivalence trial asks whether the effects of two treatments are statistically equivalent.
What Did the Researchers Do and Find?
The researchers followed 500 antiretroviral-naïve HIV-infected women with a low CD4 cell count living in seven African countries, half of whom received NVP-based ART and half of whom received LPV/r-based ART, for an average of 118 weeks and recorded the time to virologic failure (the presence of virus in the blood above pre-specified levels) or death among the participants. Forty-two women in the NVP arm reached this primary endpoint (37 virologic failures and five deaths) compared to 50 women in the LPV/r arm (43 virologic failures and seven deaths), a result that indicates equivalent virologic efficacy according to preset statistical criteria. During the initial assigned treatment, similar proportions of women in both treatment arms developed serious drug-related signs and symptoms and laboratory abnormalities. However, whereas 14% of the women in the NVP arm discontinued treatment because of adverse effects, none of the women in the LPV/r arm discontinued treatment. Finally, nearly half of the women tested in the NVP arm but only 15% of the women tested in the LVP/r arm had developed any drug resistance at the time of virologic failure.
What Do These Findings Mean?
These findings indicate that, among HIV-infected, treatment-naïve African women, initial NVP-based ART is as effective as LPV/r-based ART in terms of virologic failure and death although more women in the NVP arm discontinued treatment or developed new drug resistance than in the LPV/r arm. Several limitations of this study may affect the accuracy of these findings. In particular, some of the study participants may have been exposed to single-dose NVP during childbirth to prevent mother-to-child transmission of HIV; in a parallel randomized trial, the researchers found that LPV/r-based ART was superior to NVP-based ART among women with prior exposure to single-dose NVP. Moreover, the duration of the current study means the long-term effects of the two treatments cannot be compared. Nevertheless, these findings support the WHO recommendation of NVP-based ART with careful early toxicity monitoring as an initial affordable and effective HIV treatment regiment in resource-limited settings, until access to better-tolerated and more potent regimens is possible.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001236.
Information is available from the US National Institute of Allergy and Infectious Diseases on all aspects of HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS, and summaries of recent research findings on HIV care and treatment (in several languages)
Information is available from Avert, an international AIDS charity on many aspects of HIV/AIDS, including detailed information on HIV treatment and care (in English and Spanish)
WHO provides information about universal access to AIDS treatment (in English, French and Spanish); its 2010 ART guidelines can be downloaded
More information about this trial, the OCTANE trial, is available
MedlinePlus provides detailed information about nevirapine and lopinavir/ritinovir (in English and Spanish)
Patient stories about living with HIV/AIDS are available through Avert; the nonprofit website Healthtalkonline also provides personal stories about living with HIV, including stories about taking anti-HIV drugs and the challenges of anti-HIV drugs
doi:10.1371/journal.pmed.1001236
PMCID: PMC3373629  PMID: 22719231
13.  Temporal Reduction of HIV Type 1 Viral Load in Breast Milk by Single-Dose Nevirapine during Prevention of MTCT 
AIDS Research and Human Retroviruses  2009;25(12):1261-1264.
Abstract
Short-course zidovudine (ZDV) with or without a single dose of nevirapine (sdNVP) is widely used to prevent mother-to-child HIV transmission (PMTCT). However, more data on viral load in breast milk following pMTCT regimens are needed. In a randomized PMTCT study in Botswana, in which half of the women received sdNVP in labor, stored samples from mothers assigned to breastfeed were analyzed for HIV-1 RNA in breast milk supernatant. A total of 527 samples from 282 women, collected at delivery, 2 weeks, 2 months, and 5 months postpartum were available for testing. Cell-free breast milk HIV-1 RNA was detectable (>40 copies/ml) in 44.8% (236/527) of samples analyzed. Women randomized to sdNVP + ZDV were more likely to have undetectable breast milk viral loads at 2 weeks postpartum compared with those who received ZDV alone (67.8% vs. 38.5%, p = 0.002). By 2 months postpartum the difference between study arms disappeared, and 43.8% of women who received sdNVP + ZDV had undetectable HIV-1 RNA compared to 53.8% of the ZDV alone group (p = 0.19) and 60.5% vs. 64.5%, respectively, at month 5 (p = 0.61.) The addition of sdNVP to antenatal short-course AZT resulted in significantly reduced breast milk viral loads at 2 weeks postpartum suggesting a reduced risk of MTCT during the early postpartum period. However, viral loads in both study arms were comparable at 2 and 5 months postpartum, suggesting that the receipt of sdNVP in labor may defer rather than blunt the postpartum viral load rebound seen in breast milk after the discontinuation of ZDV.
doi:10.1089/aid.2009.0037
PMCID: PMC2828251  PMID: 20001515
14.  Slower Clearance of Nevirapine Resistant Virus in Infants Failing Extended Nevirapine Prophylaxis for Prevention of Mother-to-Child HIV Transmission 
Abstract
Nevirapine resistance mutations arise commonly following single or extended-dose nevirapine (ED-NVP) prophylaxis to prevent mother-to-child transmission (PMTCT) of human immunodeficiency virus (HIV), but decay within 6–12 months of single-dose exposure. Use of ED-NVP prophylaxis in infants is expected to rise, but data on decay of nevirapine resistance mutations in infants in whom ED-NVP failed remain limited. We assessed, in Ethiopian infants participating in the Six-Week Extended Nevirapine (SWEN) Trial, the prevalence and persistence of nevirapine resistance mutations at 6 and 12 months following single-dose or up to 6 weeks of ED-NVP, and correlated their presence with the timing of infection and the type of resistance mutations. Standard population genotyping followed by high-throughput cloning were done on dried blood spot samples collected during the trial. More infants who received ED-NVP had nevirapine resistance detected by standard population genotyping (high frequencies) at age 6 months compared with those who received single-dose nevirapine (SD-NVP) (58% of 24 vs. 26% of 19, respectively; p = 0.06). Moreover, 56% of ED-NVP-exposed infants with nevirapine resistance at age 6 months still had nevirapine resistance mutations present at high frequencies at age 1 year. Infants infected before 6 weeks of age who received either SD- or ED-NVP were more likely to have Y181C or K103N; these mutations were also more likely to persist at high frequencies through 1 year of age. HIV-infected infants in whom ED-NVP prophylaxis fails are likely to experience delayed clearance of nevirapine-resistant virus in the first year of life, which in turn places them at risk for early selection of multidrug-resistant HIV after initial therapy with nonnucleoside reverse transcriptase inhibitor-based regimens.
doi:10.1089/aid.2010.0346
PMCID: PMC3149453  PMID: 21241214
15.  Effectiveness of Non-nucleoside Reverse-Transcriptase Inhibitor-Based Antiretroviral Therapy in Women Previously Exposed to a Single Intrapartum Dose of Nevirapine: A Multi-country, Prospective Cohort Study 
PLoS Medicine  2010;7(2):e1000233.
In a comparative cohort study, Jeffrey Stringer and colleagues investigate the risk of ART failure in women who received single-dose nevirapine for PMTCT, and assess the duration of increased risk.
Background
Intrapartum and neonatal single-dose nevirapine (NVP) reduces the risk of mother-to-child HIV transmission but also induces viral resistance to non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs. This drug resistance largely fades over time. We hypothesized that women with a prior single-dose NVP exposure would have no more than a 10% higher cumulative prevalence of failure of their NNRTI-containing antiretroviral therapy (ART) over the first 48 wk of therapy than would women without a prior exposure.
Methods and Findings
We enrolled 355 NVP-exposed and 523 NVP-unexposed women at two sites in Zambia, one site in Kenya, and two sites in Thailand into a prospective, non-inferiority cohort study and followed them for 48 wk on ART. Those who died, discontinued NNRTI-containing ART, or had a plasma viral load ≥400 copies/ml at either the 24 wk or 48 wk study visits and confirmed on repeat testing were characterized as having failed therapy. Overall, 114 of 355 NVP-exposed women (32.1%) and 132 of 523 NVP-unexposed women (25.2%) met criteria for treatment failure. The difference in failure rates between the exposure groups was 6.9% (95% confidence interval [CI] 0.8%–13.0%). The failure rates of women stratified by our predefined exposure interval categories were as follows: 47 of 116 women in whom less than 6 mo elapsed between exposure and starting ART failed therapy (40%; p<0.001 compared to unexposed women); 25 of 67 women in whom 7–12 mo elapsed between exposure and starting ART failed therapy (37%; p = 0.04 compared to unexposed women); and 42 of 172 women in whom more than 12 mo elapsed between exposure and starting ART failed therapy (24%; p = 0.82 compared to unexposed women). Locally weighted regression analysis also indicated a clear inverse relationship between virologic failure and the exposure interval.
Conclusions
Prior exposure to single-dose NVP was associated with an increased risk of treatment failure; however, this risk seems largely confined to women with a more recent exposure. Women requiring ART within 12 mo of NVP exposure should not be prescribed an NNRTI-containing regimen as first-line therapy.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Every year, acquired immunodeficiency syndrome (AIDS) kills nearly 300,000 children. At the end of 2008, 2.1 million children were positive for the human immunodeficiency virus (HIV), the cause of AIDS, and in that year alone more than 400,000 children were newly infected with HIV. Most HIV-positive children acquire the virus from their mothers during pregnancy or birth or through breastfeeding, so-called mother-to-child transmission (MTCT). Without intervention, 15%–30% of babies born to HIV-positive women become infected with HIV during pregnancy and delivery, and a further 5%–20% become infected through breastfeeding. These rates of infection can be greatly reduced by treating the mother and her newborn baby with antiretroviral drugs. A single dose of nevirapine (a “non-nucleoside reverse transcriptase inhibitor” or NNRTI) given to the mother at the start of labor and to the baby soon after birth reduces the risk of MTCT by nearly a half; a further reduction in risk can be achieved by giving the mother and her baby additional antiretroviral drugs during pregnancy, around the time of birth, and while breast-feeding.
Why Was This Study Done?
Single-dose nevirapine is the mainstay of MTCT prevention programs in many poor countries but can induce resistance to nevirapine and to other NNRTIs. The drugs used to treat HIV infections fall into several different classes defined by how they stop viral growth. HIV can become resistant to any of these drugs and a virus strain that is resistant to one member of a drug class is often also resistant to other members of the same class. Because most first-line antiretroviral therapies (ARTs; cocktails of antiretroviral drugs) used in developing countries contain an NNRTI and because HIV-positive mothers eventually need ART to safeguard their own health, the resistance to NNRTIs that is induced in women by single-dose nevirapine might decrease the chances that ART will work for them later. In this multi-country, prospective cohort study, the researchers compare the effectiveness of NNRTI-containing ART in a group (cohort) of women previously exposed to single-dose nevirapine during childbirth to its effectiveness in a group of unexposed women. They also investigate whether the length of time between nevirapine exposure and ART initiation affects ART effectiveness.
What Did the Researchers Do and Find?
The researchers enrolled 355 HIV-positive nevirapine-exposed women and 523 HIV-positive nevirapine-unexposed women in Zambia, Kenya, and Thailand who were just starting NNRTI-containing ART and followed them for 48 weeks. They defined ART failure as death, discontinuation of NNRTI-containing ART, or a high virus load in the blood (virologic failure) at 24 or 48 weeks. ART failed in nearly a third of the nevirapine-exposed women but in only a quarter of the nevirapine-unexposed women. Women who began ART within 6 months of taking single-dose nevirapine to prevent MTCT were twice as likely to experience ART failure as women not exposed to single-dose nevirapine. Women who began ART 7–12 months after single-dose nevirapine had a slightly increased risk of ART failure compared to unexposed women but this increased risk was not statistically significant; that is, it could have occurred by chance. Women who began ART more than 12 months after single-dose nevirapine did not have an increased risk of ART failure compared to unexposed women. Finally, the researchers used a statistical method called locally weighted regression analysis to confirm that an increase in the interval between single-dose nevirapine and ART initiation decreased the risk of virologic failure.
What Do These Findings Mean?
These findings, which confirm and extend the results of previous studies and which are likely to be generalizable to other resource-poor countries, indicate that single-dose nevirapine given to women to prevent MTCT increases their risk of subsequent ART failure. More positively, they also show that this increased failure risk is largely confined to women who begin ART within a year of exposure to nevirapine. Because of the study design, it is possible that the nevirapine-exposed women share some additional, undefined characteristic that makes them more likely to fail ART than unexposed women. Even so, these findings suggest that, provided NNRTI-containing ART is not given to HIV-positive women within a year of nevirapine exposure, single-dose nevirapine can be safely used to prevent MTCT without compromising the mother's future antiretroviral treatment options.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000233.
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS, on treatments for HIV/AIDS, and on HIV infection in infants and children
HIV InSite has comprehensive information on all aspects of HIV/AIDS
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including information on children, HIV, and AIDS and on preventing mother-to-child transmission of HIV (in English and Spanish)
UNICEF also has information about children and HIV and AIDS (in several languages)
The World Health Organization has information on mother-to-child transmission of HIV
doi:10.1371/journal.pmed.1000233
PMCID: PMC2821896  PMID: 20169113
16.  Initiation of Antiretroviral Treatment in Women After Delivery Can Induce Multiclass Drug Resistance in Breastfeeding HIV-Infected Infants 
HIV-infected breastfeeding infants acquired multi-class drug resistance (MCR) after their mothers started highly active antiretroviral therapy (HAART). MCR was more frequent in infants whose mothers started HAART by 6 months post-partum or were exclusively breastfeeding when they reported HAART use.
Background. The World Health Organization currently recommends initiation of highly active antiretroviral therapy (HAART) for human immunodeficiency virus (HIV)–infected lactating women with CD4+ cell counts <350 cells/μL or stage 3 or 4 disease. We analyzed antiretroviral drug resistance in HIV-infected infants in the Post Exposure Prophylaxis of Infants trial whose mothers initiated HAART postpartum (with a regimen of nevirapine [NVP], stavudine, and lamivudine). Infants in the trial received single-dose NVP and a week of zidovudine (ZDV) at birth; some infants also received extended daily NVP prophylaxis, with or without extended ZDV prophylaxis.
Methods. We analyzed drug resistance in plasma samples collected from all HIV-infected infants whose mothers started HAART in the first postpartum year. Resistance testing was performed using the first plasma sample collected within 6 months after maternal HAART initiation. Categorical variables were compared by exact or trend tests; continuous variables were compared using rank-sum tests.
Results. Multiclass resistance (MCR) was detected in HIV from 11 (29.7%) of 37 infants. Infants were more likely to develop MCR infection if their mothers initiated HAART earlier in the postpartum period (by 14 weeks vs after 14 weeks and up to 6 months vs after 6 months, P = .0009), or if the mother was exclusively breastfeeding at the time of HAART initiation (exclusive breastfeeding vs mixed feeding vs no breastfeeding, P = .003).
Conclusions. postpartum maternal HAART initiation was associated with acquisition of MCR in HIV-infected breastfeeding infants. The risk was higher among infants whose mothers initiated HAART closer to the time of delivery or were still exclusively breastfeeding when they first reported HAART use.
doi:10.1093/cid/cir008
PMCID: PMC3070029  PMID: 21460326
17.  Safety and Efficacy of HIV Hyperimmune Globulin (HIVIGLOB) for Prevention of Mother-to-Child HIV Transmission in HIV-1 infected Pregnant Women and their Infants in Kampala, Uganda (HIVIGLOB/NVP STUDY) 
Background
This phase III randomized clinical trial compared single dose nevirapine (sdNVP) plus HIV immunoglobulin (HIVIGLOB) to sdNVP alone for preventing maternal-to-child transmission (PMTCT) of HIV.
Primary objectives were to determine rates of HIV infection among infants, and to assess the safety of HIVIGLOB in combination with sdNVP in HIV-infected Ugandan pregnant women and their infants.
Methods
Mother-infant pairs were randomized to receive 200mg of NVP to women in labor and 2mg/kg NVP to newborns within 72 hours after birth (sdNVP arm) or to receive sdNVP plus a single intravenous 240ml dose of HIVIGLOB given to women at 36-38 weeks gestation and a single intravenous 24ml dose to newborns within 18 hours of birth (HIVIGLOB/sdNVP arm). Risk of HIV infection was determined using Kaplan-Meier and risk ratio estimates at birth, 2, 6, 14 weeks, 6 and 12 months of age.
Results
Intent-to-treat analysis included 198 HIVIGLOB/sdNVP and 294 sdNVP mother-infant pairs. At 6 months of age, the primary endpoint, there was no statistically significant difference in HIV transmission in the HIVIGLOB/sdNVP arm versus the sdNVP arm (18.7% vs.15.0%; RR =1.240 [95% CI: 0.833-1.846]; p= 0.290). Similarly, the proportion of serious adverse events in the HIVIGLOB/sdNVP and sdNVP arms, respectively for mothers (18.9% vs. 19.3%; p= 0.91) and infants (62.6% vs. 59.5%; p=0.51), were not significantly different.
Conclusion
Giving mother-infant pairs an infusion of peripartum HIV hyperimmunoglobulin in addition to sdNVP for PMTCT was as safe as sdNVP alone, but was no more effective than sdNVP alone in preventing HIV transmission.
doi:10.1097/QAI.0b013e31822f8914
PMCID: PMC3204156  PMID: 21826009
HIV; HIVIGLOB; sdNVP; breastfeeding; PMTCT; Uganda
18.  Minor resistant variants in nevirapine-exposed infants may predict virologic failure on nevirapine-containing ART 
Background
Single-dose nevirapine (sdNVP) is widely used to prevent mother-to-child transmission (PMTCT) of HIV-1. This may result in NVP resistance in both mother and infant. The significance of low levels of NVP resistance mutations in infants treated with NVP-containing antiretroviral treatment (ART) is unknown.
Objectives
To determine the presence of pre-treatment NVP resistance in HIV-infected infants with and without prior NVP exposure.
Study Design
33 HIV-1-infected infants in a PMTCT trial received NVP-containing ART (26 infants with prior NVP exposure). Plasma and buffy coat samples obtained prior to ART initiation were evaluated for drug resistance by bulk sequencing and allele-specific PCR (ASPCR).
Results
ViroSeq™ identified NVP resistance in 3 of 33 infants; all failed first-line therapy. Pre-ART plasma NVP resistance by ASPCR was detected in 9 of 16 children experiencing virologic failure compared to 4 of 17 children without virologic failure (risk ratio 2.4, CI 0.94-7.8, p=0.08). Proviral resistance was not associated with virologic failure (risk ratio 1.2, CI 0.8-2.0, p= 0.40). In the nevirapine-exposed infants, those who started ART before 7 months had higher risk of virologic failure (RR 2.3; CI 0.96-9.2; p=0.11).
Conclusions
Low level drug resistance detected in plasma after NVP exposure prior to ART initiation may be associated with virologic failure on ART, while resistance in the DNA reservoir was not predictive of treatment outcome.
doi:10.1016/j.jcv.2010.03.017
PMCID: PMC2909836  PMID: 20427228
HIV; minor variant; drug resistance; nevirapine; PMTCT
19.  Analysis of Drug Resistance in Children Receiving Antiretroviral Therapy for Treatment of HIV-1 Infection in Uganda 
Abstract
We analyzed drug resistance in HIV-infected Ugandan children who received antiretroviral therapy in a prospective, observational study (2004–2006); some children had prior single-dose nevirapine (sdNVP) exposure. Children received stavudine (d4T), lamivudine (3TC), and nevirapine (NVP); treatment was continued if they were clinically and immunologically stable. Samples with >1,000 copies/ml HIV RNA were analyzed by using the ViroSeq HIV Genotyping System (ViroSeq). Subtype A and D pretreatment samples also were analyzed with the LigAmp assay (for K103N, Y181C, and G190A). ViroSeq results were obtained for 74 pretreatment samples (35 from sdNVP-exposed children (median age, 19 months) and 39 from sdNVP-unexposed children (median age, 84 months). This included 39 subtype A, 22 subtype D, 1 subtype C, and 12 inter-subtype recombinant samples. One sample had nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance, one had nucleoside reverse transcriptase inhibitor (NRTI) resistance, and three had protease inhibitor (PI) resistance. Y181C was detected by using LigAmp in five pretreatment samples [four (14.8%) of 37 samples from sdNVP-exposed children, one (4.2%) of 24 samples from children without prior sdNVP exposure; p = 0.35]. Among children who were not virally suppressed at 48 weeks of treatment, all 12 tested had NNRTI resistance, as well as resistance to 3TC and emtricitibine (FTC); three had resistance to other NRTIs. Seven of those children had a ViroSeq result at 96 weeks of treatment; four of the seven acquired resistance to additional NRTIs by 96 weeks. In Uganda, clinically and immunologically stable children receiving nonsuppressive antiretroviral treatment regimens are at risk for development of drug resistance.
doi:10.1089/aid.2009.0164
PMCID: PMC2875950  PMID: 20455758
20.  Emergence and persistence of nevirapine (NVP) resistance in breast milk after single-dose NVP administration 
AIDS (London, England)  2010;24(4):557-561.
OBJECTIVE
Single-dose nevirapine (sdNVP) can reduce the risk of HIV vertical transmission. We assessed risk factors for NVP resistance in plasma and breast milk from sdNVP-exposed Ugandan women.
METHODS
Samples were analyzed using the Roche AMPLICOR HIV-1 Monitor Test Kit, v1.5, and the ViroSeq HIV-1 Genotyping System. NVP concentrations were determined by liquid chromatography with tandem mass spectroscopy.
RESULTS
HIV genotypes (plasma and breast milk) were obtained for 30 women 4 weeks after sdNVP (HIV subtypes: 15A, 1C, 12D, 2 recombinant). NVP resistance was detected in 12 (40%) of 30 breast milk samples. There was a non-significant trend between detection of NVP resistance in breast milk and plasma (p=0.06). There was no association of HIV resistance in breast milk with median maternal pre-NVP viral load or CD4 cell count, median breast milk viral load at 4 weeks, breast milk sodium >10 mmol/L, HIV subtype, or concentration of NVP in breast milk or plasma.
CONCLUSIONS
NVP resistance was frequently detected in breast milk 4 weeks after sdNVP exposure. In this study, we were unable to identify specific factors associated with breast milk NVP resistance.
doi:10.1097/QAD.0b013e3283346e60
PMCID: PMC3065236  PMID: 20057308
nevirapine; HIV-1; breast milk; Uganda; vertical transmission; nevirapine resistance
21.  Greater Suppression of Nevirapine Resistance With 21- vs 7-Day Antiretroviral Regimens After Intrapartum Single-Dose Nevirapine for Prevention of Mother-to-Child Transmission of HIV 
Seven- or 21-day regimens of tenofovir/emtricitabine, zidovudine/lamivudine, or lopinavir/ritonavir after single-dose nevirapine (NVP) were effective in suppressing NVP resistance detected by population genotype. Allele-specific polymerase chain reaction revealed that the 21-day regimens were significantly better at preventing the emergence of minor NVP resistance.
Background. Nevirapine (NVP) resistance emerges in up to 70% of women exposed to single-dose (sd) NVP for prevention of mother-to-child transmission of human immunodeficiency virus (HIV).
Methods. HIV-infected pregnant women were randomized to receive sdNVP and either zidovudine/lamivudine (3TC), tenofovir/emtricitabine (FTC), or lopinavir/ritonavir for either 7 or 21 days. The primary endpoint was the emergence of new NVP resistance mutations as detected by standard population genotype at 2 and 6 weeks after treatment. Low-frequency NVP- or 3TC/FTC-resistant mutants at codons 103, 181, and 184 were sought using allele-specific polymerase chain reaction (ASP).
Results. Among 484 women randomized, 422 (87%) received study treatment. Four hundred twelve (98%) women had primary endpoint results available; of these, 5 (1.2%) had new NVP resistance detected by population genotype: 4 of 215 in the 7-day arms (1.9%; K103N in 4 women with Y181C, Y188C, or G190A in 3 of 4) and 1 of 197 (0.5%; V108I) in the 21-day arms (P = .37). Among women with ASP results, new NVP resistance mutations emerged significantly more often in the 7-day arms (13/74 [18%]) than in the 21-day arms (3/66 [5%], P = .019). 3TC/FTC-resistant mutants (M184V/I) emerged infrequently (7/134 [5%]), and their occurrence did not differ by arm.
Conclusions. Three short-term antiretroviral strategies, begun simultaneously with the administration of sdNVP, resulted in a low rate (1.2%) of new NVP-resistance mutations when assessed at 2 and 6 weeks following completion of study treatment by standard genotype. ASP revealed that 21-day regimens were significantly better than 7-day regimens at preventing the emergence of minor NVP resistance variants.
Clinical Trials Registration. NCT00099632.
doi:10.1093/cid/cis1219
PMCID: PMC3588119  PMID: 23300238
nevirapine; mother-to-child transmission; pregnancy; resistance; HIV
22.  18-month occurrence of severe events among early diagnosed HIV-infected children before antiretroviral therapy in Abidjan, Côte d'Ivoire: A cohort study 
BMC Public Health  2008;8:169.
Objective
To assess the 18-month field effectiveness on severe events of a pediatric package combining early HIV-diagnosis and targeted cotrimoxazole prophylaxis in HIV-infected children from age six-week before the antiretroviral era, in Abidjan, Côte d'Ivoire.
Methods
Data from two consecutive prevention of HIV mother-to-child transmission programs were compared: the ANRS 1201/1202 Ditrame-Plus cohort (2001–2005) and the pooled data of the ANRS 049a Ditrame randomized trial and its following open-labeled cohort (1995–2000), used as a reference group. HIV-infected pregnant women ≥ 32–36 weeks of gestation were offered a short-course peri-partum antiretroviral prophylaxis (ZDV in Ditrame, and ZDV ± 3TC+single-dose (sd) NVP in Ditrame-Plus). Neonatal prophylaxis was provided in Ditrame-Plus only: 7-day ZDV and sdNVP 48–72 h after birth. A 6-week pediatric HIV-RNA diagnosis was provided on-line in the Ditrame-Plus while it was only oriented on clinical symptoms in Ditrame. Six-week HIV-infected children received a daily cotrimoxazole prophylaxis in Ditrame-Plus while no prophylaxis was provided in Ditrame. The determinants of severe events (death or hospitalization > 1 day) were assessed in a Cox regression model.
Results
Between 1995 and 2003, 98 out of the 1121 live-births were diagnosed as HIV-infected in peri-partum: 45 from Ditrame-Plus and 53 from Ditrame. The 18-month Kaplan-Meier cumulative probability of presenting a severe event was 66% in Ditrame-Plus (95% confidence interval [95%CI]: 50%–81%) and 77% in Ditrame (95%CI: 65%–89%), Log Rank test: p = 0.47. After adjustment on maternal WHO clinical stage, maternal death, 6-week pediatric viral load, birth-weight, and breastfeeding exposure, the 18-month risk of severe event was lower in Ditrame-Plus than in Ditrame (adjusted Hazard Ratio (aHR): 0.55, 95%CI: 0.3–1.1), although the difference was not statistically significant; p = 0.07). Maternal death was the only variable determinant of the occurrence of severe events in children (aHR: 3.73; CI: 2.2–11.2; p = 0.01).
Conclusion
Early cotrimoxazole from 6 weeks of age in HIV-infected infants seemed to reduce probability of severe events but the study lacked statistical power to prove this. Even with systematic cotrimoxazole prophylaxis, infant morbidity and mortality remained high pointing towards a need for early pediatric HIV-diagnosis and antiretroviral treatment in Africa.
doi:10.1186/1471-2458-8-169
PMCID: PMC2416449  PMID: 18492259
23.  HIV-1 Drug Resistance Emergence among Breastfeeding Infants Born to HIV-Infected Mothers during a Single-Arm Trial of Triple-Antiretroviral Prophylaxis for Prevention of Mother-To-Child Transmission: A Secondary Analysis 
PLoS Medicine  2011;8(3):e1000430.
Analysis of a substudy of the Kisumu breastfeeding trial by Clement Zeh and colleagues reveals the emergence of HIV drug resistance in HIV-positive infants born to HIV-infected mothers treated with antiretroviral drugs.
Background
Nevirapine and lamivudine given to mothers are transmitted to infants via breastfeeding in quantities sufficient to have biologic effects on the virus; this may lead to an increased risk of a breastfed infant's development of resistance to maternal antiretrovirals. The Kisumu Breastfeeding Study (KiBS), a single-arm open-label prevention of mother-to-child HIV transmission (PMTCT) trial, assessed the safety and efficacy of zidovudine, lamivudine, and either nevirapine or nelfinavir given to HIV-infected women from 34 wk gestation through 6 mo of breastfeeding. Here, we present findings from a KiBS trial secondary analysis that evaluated the emergence of maternal ARV-associated resistance among 32 HIV-infected breastfed infants.
Methods and Findings
All infants in the cohort were tested for HIV infection using DNA PCR at multiple study visits during the 24 mo of the study, and plasma RNA viral load for all HIV-PCR–positive infants was evaluated retrospectively. Specimens from mothers and infants with viral load >1,000 copies/ml were tested for HIV drug resistance mutations. Overall, 32 infants were HIV infected by 24 mo of age, and of this group, 24 (75%) infants were HIV infected by 6 mo of age. Of the 24 infants infected by 6 mo, nine were born to mothers on a nelfinavir-based regimen, whereas the remaining 15 were born to mothers on a nevirapine-based regimen. All infants were also given single-dose nevirapine within 48 hours of birth. We detected genotypic resistance mutations in none of eight infants who were HIV-PCR positive by 2 wk of age (specimens from six infants were not amplifiable), for 30% (6/20) at 6 wk, 63% (14/22) positive at 14 wk, and 67% (16/24) at 6 mo post partum. Among the 16 infants with resistance mutations by 6 mo post partum, the common mutations were M184V and K103N, conferring resistance to lamivudine and nevirapine, respectively. Genotypic resistance was detected among 9/9 (100%) and 7/15 (47%) infected infants whose mothers were on nelfinavir and nevirapine, respectively. No mutations were detected among the eight infants infected after the breastfeeding period (age 6 mo).
Conclusions
Emergence of HIV drug resistance mutations in HIV-infected infants occurred between 2 wk and 6 mo post partum, most likely because of exposure to maternal ARV drugs through breast milk. Our findings may impact the choice of regimen for ARV treatment of HIV-infected breastfeeding mothers and their infected infants.
Trial Registration
ClinicalTrials.gov NCT00146380
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Globally, more than 2 million children are infected with the human immunodeficiency virus (HIV) that causes acquired immunodeficiency syndrome (AIDS), and half a million children are newly infected every year. These infections are mainly the result of mother-to-child transmission (MTCT) of HIV during pregnancy, labor and delivery, or through breastfeeding. MTCT can be greatly reduced by treating HIV-positive mothers and their babies with antiretroviral drugs (ARVs). Without ARVs, up to half of babies born to HIV-positive mothers become infected with HIV. This rate of transmission falls to below 5% if a combination of three ARVs is given to the mother throughout pregnancy. Unfortunately, this triple-ARV therapy is too expensive for use in the resource-limited countries where most MTCT occurs. Instead, many such countries have introduced simpler, shorter ARV regimens such as a daily dose of zidovudine (a nucleoside reverse transcriptase inhibitor or NRTI) given to HIV-positive women during late pregnancy coupled with single-dose nevirapine (a non-nucleoside reverse transcriptase inhibitor or NNRTI) at the onset of labor, zidovudine and lamivudine (another NRTI) during labor and delivery, and single-dose nevirapine given to the baby at birth.
Why Was This Study Done?
More than 95% of HIV-exposed children are born in resource-limited settings where breastfeeding is the norm and is crucial for child survival even though it poses a risk of HIV transmission. Consequently, several recent studies have investigated whether MTCT can be further reduced by giving the mother ARVs while she is breastfeeding. In the Kisumu Breastfeeding Study (KiBS), for example, researchers assessed the effects of giving zidovudine, lamivudine, and either nevirapine or nelfinavir (a protease inhibitor) to HIV-infected women from 34 weeks of pregnancy through 6 months of breastfeeding. The results of KiBS indicate that this approach might be a safe, feasible way to reduce MTCT (see the accompanying paper by Thomas and colleagues). However, low amounts of nevirapine and lamivudine are transferred from mother to infant in breast milk and this exposure to ARVs could induce the development of resistance to ARVs among HIV-infected infants. In this KiBS substudy, the researchers investigate whether HIV drug resistance emerged in any of the HIV-positive infants in the parent study.
What Did the Researchers Do and Find?
In KiBS, 32 infants were HIV-positive at 24 months old; 24 were HIV-positive at 6 months old when their mothers stopped taking ARVs and when breastfeeding was supposed to stop. The researchers analyzed blood samples taken from these infants at various ages and from their mothers for the presence of HIV drug resistance mutations (DNA changes that make HIV resistant to killing by ARVs). They detected no resistance mutations in samples taken from 2-week old HIV-positive infants or from the infants who became infected after the age of 6 months. However, they found resistance mutations in a third and two-thirds of samples taken from 6-week and 6-month old HIV-positive infants, respectively. The commonest mutations conferred resistance to lamivudine and nevirapine. Moreover, resistance mutations were present in samples taken from all the HIV-positive infants whose mothers who had received nelfinavir but in only half those taken from infants whose mothers who had received nevirapine. Finally, most of the mothers of HIV-positive infants had no HIV drug resistance mutations, and only one mother-infant pair had an overlapping pattern of HIV drug resistance mutations.
What Do These Findings Mean?
These findings indicate that, in this KiBS substudy, the emergence of HIV drug resistance mutations in HIV-infected infants whose mothers were receiving ARVs occurred between 2 weeks and 6 months after birth. The pattern of mutations suggests that drug resistance most likely arose through exposure of the infants to low levels of ARVs in breast milk rather than through MTCT of drug-resistant virus. These findings need confirming but suggest that infants exposed to ARVs through breast milk—a situation that may become increasingly common given the reduction in MTCT seen in KiBS and other similar trials—should be carefully monitored for HIV infection. Providers should consider the mothers' regimen when choosing treatment for infants who are found to be HIV-infected despite maternal triple drug prophylaxis. Infants exposed to a maternal regimen with NNRTI drugs should receive first-line therapy with lopinavir/ritonavir, a protease inhibitor. The significance of the NRTI mutations such as M184V with regard to response to therapy needs further evaluation. The M184V mutation may result in hypersensitization to other NRTI drugs and delay or reverse zidovudine resistance. Given the limited availability of alternative drugs for infants in resource-limited settings, provision of the standard WHO-recommended first-line NRTI backbone, which includes 3TC, with enhanced monitoring of the infant to ensure virologic suppression, could be considered. Such an approach should reduce both illness and morbidity among infants who become HIV positive through breastfeeding.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/ 10.1371/journal.pmed.1000430.
The accompanying PLoS Medicine Research article by Thomas and colleagues describes the primary findings of the Kisumu Breastfeeding Study
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
HIV InSite has comprehensive information on HIV/AIDS
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including information on children, HIV, and AIDS and on preventing mother-to-child transmission of HIV (in English and Spanish)
UNICEF also has information about children and HIV and AIDS (in several languages)
The World Health organization has information on mother-to-child transmission of HIV (in several languages), and guidance on the use of ARVs for preventing MTCT
doi:10.1371/journal.pmed.1000430
PMCID: PMC3066134  PMID: 21468304
24.  Effects of Short-Course Zidovudine on the Selection of Nevirapine-Resistant HIV-1 in Women Taking Single-Dose Nevirapine 
The Journal of Infectious Diseases  2012;205(12):1811-1815.
Single-dose nevirapine (sdNVP) given to prevent mother-to-child-transmission of HIV-1 selects NVP-resistance. Short-course zidovudine (ZDV) was hypothesized to lower rates of NVP-resistance. HIV-1 infected pregnant women administered sdNVP with or without short-course ZDV were assessed for HIV-1 mutations (K103N, Y181C, G190A, and V106M) prior to delivery and postpartum. Postpartum NVP-resistance was lower among 31 taking ZDV+sdNVP compared to 33 taking only sdNVP (35.5% vs 72.7%; χ2 P = .003). NVP mutants decayed to <2% in 24/35 (68.6%) at a median 6 months postpartum, with no differences based on ZDV use (logrank P = .99). Short-course ZDV was associated with reduced NVP-resistance mutations among women taking sdNVP.
doi:10.1093/infdis/jis282
PMCID: PMC3415891  PMID: 22492850
25.  A Comparison of 3 Regimens to Prevent Nevirapine Resistance Mutations in HIV-Infected Pregnant Women Receiving a Single Intrapartum Dose of Nevirapine 
Nevirapine resistance is common after single-dose nevirapine therapy to prevent mother-to-child transmission of HIV infection. A 7-day tail of highly active combination therapy or 1 month of dual therapy prevents most nevirapine resistance to minimal toxicity.
Background. Intrapartum single-dose (SD) nevirapine (NVP) reduces perinatal transmission of human immunodeficiency virus (HIV) infection but selects for NVP-resistant virus, which compromises subsequent NVP-based therapy. A 1-week “tail” of lamivudine and zidovudine after SD-NVP decreases the risk of resistance. We hypothesized that increasing the duration or potency of the tail would further reduce this risk to <10%, using a sensitive assay to measure resistance.
Methods. HIV-infected pregnant Thai women with a CD4 cell count >250 cells/μL, most receiving zidovudine, were randomized at 28–38 weeks gestation to receive 1 of 3 intrapartum and postpartum regimens: (A) zidovudine plus enteric-coated didanosine plus lopinavir and ritonavir for 7 days, (B) zidovudine plus enteric-coated didanosine for 30 days, or (C) regimen 1 for 30 days. The incidence of NVP resistance mutations at day 10 or week 6 post partum in each arm was compared with that of a historical comparison group who received prenatal zidovudine and SD-NVP. NVP resistance was identified by consensus sequencing and a sensitive oligonucleotide ligation assay (OLA).
Results. At entry, the 169 participants had a median CD4 cell count of 456 cells/μL and an HIV load of 3.49 log10 copies/mL. The incidence of mutations in each of the 3 P1032 arms was 0% by sequencing and 1.8%, 7.1%, and 5.3% by OLA in arms A, B, and C, respectively, compared with 13.4% by sequencing and 29.4% by OLA in the comparison group (P < .001 for each study arm vs comparison group). Grade 4 anemia developed in 1 woman.
Conclusions. A 7-day tail of highly active combination therapy or 1 month of dual therapy after SD-NVP prevents most NVP resistance to minimal toxicity.
Clinical Trials Registration. The IMPAACT P1032 Clinical Trial is NCT00109590, and the PHPT-2 Clinical Trial is NCT00398684.
doi:10.1093/cid/cir798
PMCID: PMC3245730  PMID: 22144539

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